Objective To determine the effects of insulin resistance (IR) on bone metabolism and vitamin D metabolism in the elderly patients with diabetes mellitus(DM). Methods A total of 55 patients with type 2 DM at the age ranging from 65 to 89 years admitted in our department from January 2011 to December 2013 were recruited in this study. All of them were tested for oral glucose tolerance test, insulin release test and C-peptide release test. Serum levels of vitamin D3 (VitD3) and parathyroid hormone (PTH), and biomarkers for bone metabolism, including osteocacin (OCN) and carboxy-terminal β collagen crosslinks (β-CTX) were also detected. Bone mineral density (BMD) was measured by dual energy X-ray absorptiometry. Correlation analysis was performed on the effects of glucose metabolism and IR on bone metabolism. Results In the cohort, the serum level of glycosylated hemoglobin (HbA1c) was negatively correlated with that of VitD3 (r＝-0.42, P＝0.019), but positively with PTH (r＝0.40, P＝0.05). PTH was also positively related to fasting C peptide (FCP)( r＝0.40, P＝0.015) and Homeostasis Model Assessment(HOMA-β) (r＝0.56, P＝0.004). Bone formation marker OCN was in a positive correlation with HOMA-calretnin (HOMA-CR, r＝0.461, P＝0.031), while PTH was positively related to HOMA-CR either (r＝0.43, P＝0.028). But no correlation was seen in T values of BMD from every region of the total body with blood glucose, HbA1c, HOMA-β, HOMA-CR and bone metabolic markers. Conclusion For aged patients with diabetes, it is of great clinical significance to ameliorate IR and timely treat VitD deficiency or insufficiency in order to prevent osteoporosis.